Process for production of gasoline from petroleum hydrocarbons



Oct 3, 1933. A. D. SMITH ET AL PROCESS FOR PRODUCTION OF GASOLINE FROM PETROLEUM HYDROCARBONS Filed June 19. 1929 2 Sheets-Sheet l Oct. 3, 1933. A. D. SMITH Er AL PROCESS FOR PRODUCTION OF' GASOLINE FROM PETROLEUM HYDROCARBONS Filed June 19, 1929 2 Sheets-Shet 2 Inl/'enforci- Patented Oct. 3, 1933 vuNiTEo-STATES mocsss Foa PATENT OFFICE l 1,928,905. l Y. PaonUc'rloN or GASoLINE sv claim. (ci. iss-sn) This invention relates to certain improvements in the treatment of petroleumhydrocarbons. and particularly to a process for thecontinuous separation of. natural or gasoline. existent therein,

i concurrently with the continuous productionfrom thenon-g'asoline fractions thereof, of. highly volatile cracked and/or specially converted high benzoleequivalent gasoline, asthe sole objectives.

In the ordinary treatment of crude petroleum, or a cracking stock containing appreciable quantities of natural gasoline, the: latter product is removed by fractional distillation-under atmos pheric pressure, and variousselectivefractions directly or indirectly obtainedfrom the remainto cracking conditions involving relatively high temperatures` and pressures; such separate and independent treatments not onlyA producing the desired'gasoline objectives, but also products of relatively low market value, such as. distillate, fuel oil and/or coke and gas, in varyin quantities dependent upon .the method of cracking vem- Played. Y d u While cracking of` intermediately produced recycle stock is'more or less vsuccessfully accomplished in many cracking processesthe conversion of relatively light distillates` into desirable gasoline fractions, inv apparatus `primarily fle` 'signed for cracking. products of relatively high 30, specific gravity,.is commonly attendedwith dilli` l culty. 'Ihe prevention of fuel oil asan end product ofr cracking has been variouslyattempted: Thus; eithera preliminary distillationat` atmospheric pressure, whereby. an easily'convertible distillate is obtainedor severe crackingV con?v ditions have been suggested; either methodL being uneconomic in heat consumption, and producing large quantities of coke of relatively low market value. It has been further proposed to filter, centrifuge or precipitate suspended carbon or high molecular weight complexes fromthe degraded stillcontents, returning the clarified stock to the system for furtherconversiongbut such methods are open to the objection ofY handling large quantities of material,A attendant with frequent cloggings of the apparatus, and large lowes of radiant heat. A general'` object of this invention is to continuously and economicallyei'- fect, .throughthe application of one primary sourceofheat, and the subsequent utilization of .the waste and indirect energy therefrom, the complete revning of a., petroleum hydrocarbon intosuperior gasolinewithoutproduction of distillateor fuel oilendfproducts; and to accomplish suchA objective with a formation of der,` are separately and independently subjected` ilxed gas, free carbon and/or amorphous derivatives thereof. l i 4 V A further general objective*oftheJinvention is to effect the continuous separation of the nat' ural gasoline content of a crude oil `or cracking so stock by simple fractionation, concurrently with, and by the agency v .oLthe indirect heat from a combination liquid" and vapor phase process; wherein the reduced stock from such primary separation is continuously cracked in liquid phase, e5, the'heavier by-'products from such liquid phase treatment progressively cracked inv like phase, the relativelyplight,A nonfgasollne by-products from; such liquid phasetreatment continuously cracked' in vapor phase,l and the less preferred 70V i products fromlsuch vapor phase, treatment continuously cracked inlikephase; with gasoline of preferred market specilications asV the sole objective. i l An. additional Ageneral objectiveof the inven- 75. tion is to elect .the above describedseparation 'ofV natural gasoline. andthe respective conversions inlquid and. vapor phase at temperatures and under.v pressures best suited for such treatf ments; as to produce ultimate maximum gasoline yields,y coordinated to` the instrumentality of'the heat initially appliedlto the liquid phase treatment.-

.In."such` liquid phase` treatment, the previously mentioned V.preheated reduced stock, together with'. other similarly heated intermediates to be presently describedfis continuously charged to a crackings'till, wherecontinuous cracking iseffected in liquid phase at a temperature and under a. pressure'bestsuited for ultimatemaxi- 9.0 mum4 gasoline production; such ultimate yield being aconcurrent function of immediate gasolineproduction Vand the accompanying degree ofv degradation of the reacting medium.

A highly important object of the invention is therefore,` to continually subject such cracking stock in, a still, while maintaining positivecyclic circulation therein,fto a temperature and-under pressurebest suited for immediate maximum gasoline:productiony compatible with a controlled Adegradation of the reacting still content; preferably` regulating such degradation, by operating under such temperature and pressure, as to produce a predominance of complex hydrocarbon. pmymerides somme in the reacting; medium, ratherfthan free carbon; and to achieve such` objectiveat. a temperature andunder a pressure lessl thanotherwis'epossible by reasonof a uniform absorption otfiheat, approaching the vanisliiiigpoint of vaifnaremaiau man portions of the 1-10 culation there maintained.

Another important object of the invention is to continuously remove from the still, while effecting y continuousy cracking,n and-{maintaining positive liquid cyclic circulation therein, a suflicient quantity of controlled degraded stock to a zone of reduced pressure, as to produce therein after separation and removal therefrom of a sub.- stantial portion of such degraded stock asrecycle vapor, a further reduced residuum so supersaturated with diflicultly soluble high molecular weight complex polymerides as to causev partial separation thereof.

An additional object of the inventionis to continuously charge to the still, while maintaining positive liquid cyclic circulation therein, with ac-v companying continuous production and release lof gasoline, return of reflux and withdrawalof degraded stock in the manner previously mentioned, a sufficientv quantity of preheatedch'arging stock as to maintain in such still a substantially constant liquid level. Y i Y l IA further object'of the invention is to continuously introduce to such still with such preheated charging stock, an, adsorptive c oagulant, such' as lime, beauxite or other material producing a like effectj` to further continuously,releaseltherefrom intoa low pressure' vapor lseparator such" above described degradedstock,"together with its proportionate quantityV of `ad's'o'rptive coagulant; originallyintroducing an amount of such'coag'ulant,- and continuously withdrawing such aquantity of degraded stock; as Ato produce: in such'jvapor separatoriafter reduction o fv pressure therein Aand removal of the vaporized recycleffstock fractionstherefrom, a`further reduced residuum and a` partially 'coagulat'ed suspended complex of hydrocarbon polymerides of high molecular weight, free carbon 'and adsorptive ycoagulant; with such coagulant originally introduced in such quantit'y,'as to effect additional partial coagulation upon Vfurther separation of lessjsoluble comreduced residuum.

` plexes by reduction in temperature'of the further 'A' correlative object rof inventionfin conjunction' with the steps describedin-*thepreceding paragraph, is to originally continuously introduce Aa Asufficient quantitypf limeV andy/or-other adsorptive ,coagul ant, as to impart to the. previ-` ously mentioned complex a specific'gravityinsvufci'ent to substantially affect its suspension in the previously mentioned further reduced residuum, butof such differential from the latter as to cause eventual precipitation from such residuum in a z'one of repose, and 'at the same` time a lporosity and yabsence of gummy and sticky qualities, ordinarily causing ,clogging in subsequent filtering or centrlfuging operations. Q

An additional object of the invention is to initially substantially evaporatemin a Vvaporizing zone,fheat e'd by an exchanger through which the f previouslyA describedA degraded stock is constantly circulated, the intermediate distillate dephlegmated from the crude gasoline produced under liquid phase treatment; to progressivelysimilarlyevaporate in such zone by such previously described source of heat vthe corresponding intermediate produced under vapor phase treatment offthe first intermediate; andV to, continuously maintaina vapor pressure in such zone of vaporizationand the thereto unrestrictedly connected vapor phase converter-)functional of such substantialvaporization; as best Vvsuited for the lmaximum production of anti-knock high '"berizole vbenzole equivalent gasoline produced under vapor phase froma single charging stock; accomplishing such objective by simple fractionation of such stock under any desired absolute pressure within the instrumentality of the indirect heat available from'the subsequent liquid phase treatment; in-

itially cracking the* reduced stock from such simple fractionation in liquid phase, progressively crackingin like phase the recycle and clarified `degraded' stock thereby obtained; initially crack- Ato the other phases describedand/or further'refinement; and generally conducting such treatmentr with maximum economic heat interchange andminimum radiation loss.

In order that 'the invention` may be the more readily understood, reference is'made to thedacvcornpanying drawings, which are identically numbered wherein the-same parts occur. Fig. 1 and 1a is a general vertical elevation, essentially `diagrammatic lin character, rather than an exact representation of instrumentalities, of apparatus adapted for carrying out the'inventionv, v .,V v A, V v

In the'accompanying drawings, 1 represents a pressure'fstill designed for cracking 'in liquid phase, comprising a bank' of tubes 2, connecting front and rear cross drums-3 and 4, the latter beingL subjacent and connected to front and rear sluiceways and 6,`themselvesalso subjacent and connected to a horizontal bulb supply drum '7; the whole forming a closed system of freely connecting'; channels. The still 1, is further provided vwith theusual accessories; liquid level gauge 8,

safety valves 9, 9', pressure gauge l0, and recordingpyrometer 11'; the vapor line 12', leading to refiuxvftower 13. From the base of the tower 13, the reflux line 14, enters the rear end of the still 1`; the latter andY the' reflux tower 13 being in 'unrestricted connection with each other.

Continuous charging of the still 1 through the reflux tower 13, -iseected by a high pressure hot oil pump 15, taking'suction from the insulated supplytank 16 and adsorptive mixing tank 17 through the lines-18 andV 19, controlled by lstop valves 18' and 19t'v respectively, and discharging through line 20'pastcheck valve 21V to top of reflux tower; while continuous withdrawalA of lthe degraded still contents is accomplished through the line 22, as controlled by valves 23, 23', 23", and automatic relief valve 24 to low pressure vapor separator 25, which may be by-pass'ed if required, by proper manipulation of valves 23', v23" and Provision for emergency or complete discharge of still is afforded through line v26, past stop valve 2'7,'to emergency cooler 28.

VContinuous positive liquid cyclic circulation of the reacting liquid in rstill 1, is vmaintained by propeller 29, located in rear sluiceway 6; such propeller being mounted" on shaft,` 30, extending Y bio '82. The `furnace 3'3, over whichVV the still assembly.

VA1 is erected, vmay be heated by any desirable means; a typical arrangement for oil and gas fuel being respectively shown by burners34 and .34. Thelwaste .heatgases from the furnace'v'33 escape through the port` 35, entering the vapor phase .cracking furnace 36, and leave therefrom by the `,duct-'3.7, breeching 38 .and .thence `by the underfground flue 39, nally passing to the atmosphere through the stack 40. V

While straight crude' or other gasoline containing hydrocarbon, may be initially -employed for ucharging purposes, and the cracking still operated under vatmospheric pressure until a suiiicient Vquantity of natural gasoline hasbeen vaporized, and enough reduced stock'accumulated lin the Abody of the still to admit ofV imposing cracking conditions; vthe continuous operation of the sys- 'tem maybe hastened by initially employing reduced crude or other hydrocarbon, free from lightmateriaL asa charging medium.

Aas Vthe desired operating pressure has been built up in the still 1, and the contents thereof have reached the desired temperature, `continuousxcharging thereto of heavier hydro-v carbons vand release of degraded ,still contents itherefrom, is begun.

Thecrude' gasoline vapors from the reflux tower 13, maintained under full still pressure, pass through the vapor line 41 to thedephlegmating tower 42, the control of vapor flow there- Yto being eiected'by proper manipulation of valves 48, 432,44, 44l and/or 45 for remote regulation; or tower may be by-passed for emergency vpur- `poses by opening stop valve 44', permitting vapor to flow through lines 41. and- 103, direct to condenser section 4,71ocated inl water cooled condenserbox 48; thecondensed gasoline accumulating in receiving tank 49,' 'fromwhence it isautomatically discharged from: the-system through the balanced valve 50, actuated by float mechanism 50. The receiving tank 49 and condenser section 47, being in unrestricted communication `with each other, are maintained at a constant pressure .less than the'apparatus preceding, by `the' automatic gas reliefvalve 49', regulated for .the desiredpoint of ,-release.Y The waste per-v manent gas escaping through valveV 49' flows through line 51 to gasburners 34', or other point of demand. Y A

The vapor lines'52 and 53 serve to conduct the ,.hot Arecycle stock vapors released in low pressure vapor separator 25, tothe crude dephlegmating tower54, control of recycle vapor flow thereto, vbeing effected by proper adjustment of valves `55 and 55'; or by a different setting of same, the `tower 54 may be by-passed to any desired degree, -and the hot Vrecycle vapors successively conducted to the heat exchangers 56, 57 and 58, 4with ,individual flow of vapor thereto controlled by proper manipulation of the valve nests 59, 59', 59"; 60, 60', 60" and 6l, 61', 61" respectively, in a manner .that will be apparent to one skilled,V in the art. The hot condensed recycle stock from the .last -exchanger employed, Vis normally conducted by rlines 52 and 62, through adjustment of -valves 63 and 63', to the insulated supply tank A16; or by a different adjustment of the samevalves,VV the recycle stock may flow to condenser section 64,

, v provided with a receiving tankand control mech- -Lanism similar to condenser section 47.

f The further reduced degraded stock from thel .low pressure vapor separator '25, Atogether `with iii-he partially coagulated, therein suspended com,-

j respectively;

- plex'of hydrocarbonA polymerides, free carbon'and adsorptive coagulant, ows through lines 66 and, 22, as controlled by stop valve to valvenest 67;v

`67', 67, controlling admission to, or by-.passing of, heat Yexchanger 68; the stock then .passing vby L, lines 69 and 70 tolters 71, 72 and 73, with Yinlets thereto controlled by valves 7l', 72' and 73' the clarified filtrate therefrom, flowing through line 74,` as controlledfby valves 71", .72" and'73" to the insulated supply tank fil-.85

Y 16 `for 'further treatment.

The Waste products of `filtrationpass 'from the system by line 75, as controlled by valves 76, ,76, and 76". respectively; VorV the filters may be by `If desired, a centrifuging, filter press` orsettling device may be substituted for the Yfilters shown. As soon as hot recycle stock vapors fromthe ,passed byopening `valve 77, the. degraded lstock l90 then iiowing byline 78'to emergency lcooler 28.

low pressure vapor separator 25 are 'produced Vin ifi-35 suiicient Vquantity to 'effect partialA vaporization of the natural gasoline content of the prime charging stock` (crude or other medium containing light ends), continuous charging of the latter is begun through line 79, by a low pressure m clarifying device, and progressively by a mixture thereof with the hot reduced crude Aand condensed recycle stock continuously flowing to such supply tank when the process is in full operation. Control of flow of the prime charging l stock through exchanger 80 is eiected `by the valvenest 81, 81' and 81; the'charging `stock then entering exchanger 82, where vit is further preheated by the .hotreduced stock flowing from the crude dephlegmating tower 54, as soon as the latter is lbrought into the scope of operation. Control of flow through exchanger 82 is effected by valve nest 83, 83' and 83"; the-preheated prime charging stock then entering top of crude dephlegmating tower 54, where the descending stream is broughtinto direct contact with the hot recycle stock lvapors and free steam, preferably superheatedentering through valves 55' and 84 f respectively.

stock flowing from filters 71, 72, land 73, or other Q95 The natural gasoline separated by such treat- 95 valves 89 and V89', or it may be subjected to other 5 refinement as desired.

The vapor line 90Vserves to conduct thedephlegmated gasoline vapor from tower 42, to

condenser section 91, such section being similarly equipped with receiving tank and controls in a no' V4* eflected through the previously described valve vnest 61, 61 and 61".

nest 60, 60 and 60". VTh'e final condensate from tower 42 may pass by lines 93, 93and 93 to circulating pump 94, or such condensate may flow by lines 93, and 95 to condenser section 96,

similarly equipped-as previously described in connection with'condenser section 4'7. Thedirection of flow of the condensate in question is effected by proper setting of the valve nests 97, 97', 97 and 98, 98", 98,respectively, a constant v liquid level being maintained in tower 42 by balanced valve 99 and oatrnechanism 99.

The circulating'l pumpl 94 forces the. condensate owing thereto, pastV check valve 100, through line 100- to' vaporizing chamber 68', wherein such condensate is substantially vaporized under a pressure correlative to the vaporization'obtained; such vaporization being effected through the agency ofl the heat exchanger 68,v

with hot degraded stock from the low pressure vapor separator 25 as al heating medium; control ofy liquid level in suchfvaporizingchamber being accomplished by balanced valve 101 and Vfloat mechanism 101;

' The vapor line 102 conducts the substantially l vaporized intermediate, usually of a distillate nature, from the vaporizing charnber'68'r to `the vaporl phase converting zone, the crude antiknock gasoline therein produced in a manner described in a copending application, ,returning by the lines 103 and 103 to the vapor phase dephlegtherefrom byline 108, and may pass direct to condenser section 110, similarly equipped as previously described, or it may enter blending tower 88 through line 109; the direction of flow being governed by proper setting of valves 111 and 111'; or such gasoline may be subjected to other refinement as desired: f Y

The'heavier vapors condensing in tower 104 are reboiled in the lower portion thereof, through the instrumentality of the heat exchanger 58, with hot recycle stock vapors as source of heat supply; control of flow through such exchanger being effected by the 4previously described, valve The final condensate from tower 104 may pass by lines 112, 93', 93 to circulating pump. 94 for subsequent progressive vvapor phase treatment, Aor such condensate may fiowvby lines 112, 95jand 95 to the previously described condenser section 96. -The direction of ow of the condensate in question is effected by proper setting of the valve nests 97, 97', and 97" and 98, 98', 98 in a manner previously described;

. a constant liquid level being maintained in tower 104 by balanced valve 113 and float mechanism 113.

v The final dephlegmated blended gasoline vapor from blending tower 88 escapes through vapor line 114 to condenser sections 115 and 115',

vsimilarly equipped as previously described; or`

such gasoline may be subjected to further treatment in vapor phase, or other method of refineand l tioned valve nest 59, 59 and 59". The final con densatefrom tower 88 may flow by the line 116 to condenser section 117 equipped as previously described, or such condensate may pass by lines 116', 93 and 93" to circulating pumpl94, for subsequent progressive vapor phase treatment; the direction of flow of such condensate being ef- `fected by proper manipulation of the valvesv V118 and 118'. A constant liquid level is maintained in the t0wer88 by balanced valve 119 and float `mechanism 119'.

To generally secure eflicient operation of the process, automatic temperature and pressure controls, recording and/or indicating thermometers and Vpressure gauges, androtner devices of like order are employedwhenever their use is desirable, although such apparatus may not be specifically mentioned or shown in the accompany'- ing drawings. Similarly all instrumentalities involving the application of heat and transfer thereof, are so insulated as to secure maximum economic heat conservation, though not so shown in the accompanying drawings or described in the above specification. v

j The'vapor phase converter, whose description is covered in a co-pending application, may be erected within the furnace zone proper'of the main liquid phase cracking still, or constructed in a separate-chamber without the system, but heated by the waste gases therefrom; and the steam supplied to the process'lmayreceive its necessary degree of superheat from the waste heat gases discharging from Athe vaporV phase conversion zone, irrespective of the location of the latter. i

What we claim is new anddesire to protect by LettersPatent is: y l

1. A process for the production of gasoline from Vhydrocarbon oils which includes the steps of heating'said hydrocarbon oils to distill off light constituents lincluding 'gasoline existing therein, fractionally condensing'and separating outY heavier ingredients from said gasoline vapors so distilled, thereafter subjecting said hydrocarbon oils to a cracking reaction under pressure in the liquid phase to evolve additional gasoline and other oil vapors therefrom, condensing the heavier'portions of the evolved vapors in two stages,'re turning the condensate from the Afirst stage vto the hydrocarbon oils subjected to said cracking reaction in the liquid phase, retaining separate the condensate from the second stage, withdrawing residual oils from said cracking reaction, reducing pressure on the oils so withdrawn while the latter are in a heatedcondition to ash a portion thereof into hot vapors7 passing a portion of said hot vapors in heat interchange with said vhydrocarbon' oils before subjecting them to said cracking reaction to heat said hydrocarbon oils and distill olf said light constituentsA as aforesaid, passing a portion of the unvaporized residual oils in heaty interchange Awiththe aforesaid heavier ingredients and condensate from the second stage to effect a substantial revaporization thereof, thereafter subjecting the resulting vapors to a cracking reaction in the vapor phase, and separately fractionating vaporized oil products from said vapor phase cracking reaction to obtain gasoline vapors and heavier liquid condensates.

2. A process vforthe production of gasoline from petroleum' hydrocarbon' oils which comprises heating a mass of hydrocarbon oils to a cracking temperature under pressure in the liquid phase to evolve vapors therefrom; separating and remov- 1 ing vaporsso evolved to a fractionating zone and mentioned.

ther-dln condensing out'avheayycondensate portion; conductingjthe remainingcvapors .toa dephlegmatingz'one ,and therein separating zout vapors; passing the unvaporized residual oils in indirect heat interchange with said condensate in said vaporizing zone therebyA heating'l said condensate to less than a cracking temperature and effecting a substantial revaporization without cracking thereof; thereafter subjecting the resulting vapors to further heatingvat a cracking temperature for a time sufficient to crack saidv vapors in the vapor phase; removing vaporized oil products from said vapor phase cracking reaction to a separate fractionatingfzone; and fractionating therein out of contact with other oil products said vaporized oil products to obtain anti-knock gasoline vapors and heavier liquid condensates.

3. A process for the production of gasoline from petroleum hydrocarbon oils which comprises heating a mass of hydrocarbon oils to a'cracking temperature under pressure in the liquid vphase to evolve vapors therefrom; separating and re- C moving vapors so evolved to a fractionating Zone and *therein` condensing outa heavy condensate portion; conducting the remaining vapors to a dephlegmating zone and therein separatingl out Yheavier fractions from said vapors as a con- Il densate; removing the condensate thus formed to a vaporizing zone; withdrawing residual oils from said mass of hydrocarbon oils undergoing cracking; reducing pressure on the residual oils so withdrawn while said oils are in a heated condiltion thereby flashing a portion thereof into hot vapors; passing the unvaporized residual oils in indirect heat interchange with said condensate in said vaporizing zone therebyY heating said condensate to less than a cracking temperature and `effecting a substantial revaporization without cracking thereof; thereafter subjecting the resulting vapors to further heating at a cracking temperature for a time sufficient to crack said vapors in the vapor phase;erernoving vaporized condensates; and introducingsaid heavier liquid condensates into saidl vaporizing zone whereby saidl condensatesA are revaporized and returned to the vapor phase cracking reaction heretofore 4. A process for the production of gasoline from petroleum hydrocarbon oils which comprises heating a mass of hydrocarbon oils to a cracking temperature under pressure in the liquid phase to evolve vapors therefrom; separating and removing vapors so evolved to a fractionating zone and therein condensing out a heavy con-v densate portion; conducting the remaining va- Y pors to a dephlegmating zone and therein separating out heavier `fractions fromrsaid vapors as a condensate leaving in the vapor state gasoline vapors formed in the liquid phase cracking reaction; removing the condensate thusformedV off; `pors `to further heating at a cracking temperainindirectrheat interchange with said condensate in said vaporizing vz'onethereby heating said con densate to lessthanA a cracking temperatureeand 5, so Withdrawn' while said oils-are'in a-heatedrcondition-therebyfflashing a portion thereof into hot vapors;k passing the unvaporized residual oils.

effecting a` substantial revaporization -without cracking thereof; rthereaftersubjecting the resulting kvapors to further Vheating at v au crackingV temperature forv a timesufiicient to crack said vaporsin the f vapor` pha'se; removingV vaporized oitproducts from said .vapor phaseraeking reaction-to a separate fraetionating zone and frac- A tionatiug therein out of contact with other oil products said'vaporized oil products to obtain anti-knock gasoline vapors and heavier liquid condensates; and'blending out of contactY with said heavier liquid condensates gasoline vapors formed in the vapor phase and liquid phase cracking reactions heretofore mentioned.

5. A process for the production of gasoline from petroleum hydrocarbon'oils which comprises initially distilling and separating gasoline fractions from said hydrocarbon oils; thereafter heating the unvaporized portion of said'hydrocarbon oils to a cracking temperature action underpressure in the liquid phase to evolve addi-V tional gasoline and other oil vapors therefrom; conducting vapors so evolved to a dephlegmating Zone and therein separating out heavier fractions from said vapors as a condensate leaving in the vapor state gasoline vapors formed in the liquid phase cracking reaction; removing the condensate thus formed to a vaporizing zone; withdrawing residual oils from said hydrocarbon oils undergoing cracking; reducing pressure on the residual oils so withdrawn while said'oils are in a heated condition thereby flashing a portion thereof into hot vapors; passing a portion of said hot vapors into direct physical contact with the hydrocarbon oils prior to cracking. thereof to distill off said gasoline fractions as aforesaid; passing the unvaporized residual oils in indirect heat interchange with said condensate in said vaporizing zone thereby heating said condensate to less than a cracking temperature and effecting a substantial revaporzation without cracking therethereafter subjecting the resulting vature for a timesuflicient to crack said vapors in the vapor phase; removing vaporized oil product from said vapor phase cracking reaction to a separate fractionating zone and, fractionating therein out of contact with other oil products lsaid vaporized oil products to obtain anti-knock gasoline vapors and heavier liquid condensates.

6. A process for the production of gasoline Vfrom petroleum hydrocarbon oils which comprises initially distilling and separating gasoline fractions fromvsaid hydrocarbon oils; thereafter heating the unvaporized portion of said hydrocarbon oils to a cracking temperature under pressure in the liquid phase to evolve additional gasoline and otherroil vapors therefrom; conducting vapors so los evolved to a dephlegmating zone and therein separating out heavier fractions from said vapors asa condensate leaving in the vapor state gasoline vapors formed in the liquid phase crackso withdrawn while said oils are in a heated condition thereby fiashing a Vportion thereof into hot vapors; passinga portion of said hot vapors into direct physical contact with the hydrocarbon oilsY prior to cracking thereof Eto distill-off said gasoline fractions as aforesaid; passing the unvaporized residual oils in indirect heat interchange with said condensate in said vaporizing zone thereby heating said condensate to less than vapor phase cracking reaction to a separate frac-A tionating zone; fractionatingvtherein out of contact with other` oil products said vaporized oil products to obtainA anti-knock gasoline vapors and heavier liquid condensates; and blending out of contactrwithsaid heavier liquid condensates'gas lineA fractions initiallyY distilled from said hydro carbon oils prior to cracking thereof and gasoline vapors formed in the vapor phase and :liquidphase cracking reactions heretofore mentioned.

ARTHUR D. SMITH. NORMAN H. RANSTEAD. l 

